1. Field of Invention
The present invention relates to a vertical semiconductor device and a manufacturing method of a vertical semiconductor device; particularly, it relates to such vertical semiconductor device and manufacturing method wherein the current crowding phenomenon of a device is mitigated.
2. Description of Related Art
Conventionally, gallium nitride (GaN) crystal epitaxial growth is performed on a silicon carbide (SiC) substrate or a sapphire substrate. Sapphire is an insulating material, so if a power device is to be manufactured on the sapphire substrate, it has to be formed laterally; that is, the electrodes of the power device are formed on the same side of the substrate. This increases the area of the power device and the manufacturing cost, and also induces the current crowding problem.
To overcome the drawback in the prior art, the present invention proposes a vertical semiconductor device and a manufacturing method thereof which decrease the device area such that the manufacturing cost is decreased, and mitigate the current crowding problem.